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Rain in a Bottle

So we got some unexpected late summer rain out here. When I say rain, I really mean drizzle. In California where summer rain is rare especially during our drought, there are many happy people out today doing the rain dance! So, what a great opportunity to show the superheroes how rain really forms. This is a super easy experiment which pretty much uses ice and water. No excuses! Try this!

Here’s what you need to get started:

Clear bottle with a cap (We used a 1L water bottle, but any water bottle will do.)

Very warm water

Ice cubes

Scissors

Blue food coloring (optional)

Cut the top third portion of the bottle with scissors.

Add very warm water to the bottom portion of the bottle. We added 2 drops of blue food coloring to mimic the ocean. You can see the water evaporating on the sides already.

Invert the top portion and fill it with ice. Be sure to put the cap on so the cold water doesn’t drip out.

Watch as the water begins to condense on the side. My 5 year old had already learned this at school and used fancy science terms when I asked him what was going on. He said, “Mummy, the blue water is evaporating and then dripping down when it gets cold from the ice. I think it’s called conversation.” Haha! I corrected him that it was condensation 🙂

See how easy that was. And if you don’t have a plastic bottle, just use a clear bowl with a plate of ice on top. It should still work.

The Science behind the Activity:

The warm water in the bottom begins to evaporate and turn to a gas. When the gas molecules of water reach the cold ice, they cool down and turn back to liquid water and drip down the side, like rain. The “foggy” air inside the bottle simulates how clouds form, although they will not form in this experiment. In the atmosphere, water evaporates from the sea, oceans, land, etc… and condenses when it reaches the colder upper atmosphere. This condensation causes clouds to form. When the clouds get heavy enough, the water falls down to earth in the form of precipitation as rain or snow.